I really hope there are a lot of extras AND the release(s) aren't milked (i.e. 6 months after first release, another DVD is released titled 'platinum edition' with tons of extras).
Now you know
that isn't going to happen.
First release, bog standard movie with a few bits that you can already see on You Tube.
Second release: directors cut with extended interviews with cast and production.
Just before Christmas: The Collectors' Edition.: 2 DVD set with deleted scenes, in depth making of the movie, interviews with everyone who Cameron Mackintosh thinks is relevant and a nice shiny libretto and stills.
It'll cost an arm and a leg, but Hey, it's just the thing to buy as a Christmas present, so spend the extra.
Cameron Mackintosh knows me too well. I'll buy the bloody lot